Transient Upstream Mesoscale Structures: Drivers of Solar-Quiet Space Weather

Abstract

In recent years, it has become increasingly clear that space weather disturbances can be triggered by transient upstream mesoscale structures (TUMS), independently of the occurrence of large-scale solar wind (SW) structures, such as interplanetary coronal mass ejections and stream interaction regions. Different types of magnetospheric pulsations, transient perturbations of the geomagnetic field and auroral structures are often observed during times when SW monitors indicate quiet conditions, and have been found to be associated to TUMS. In this mini-review we describe the space weather phenomena that have been associated with four of the largest-scale and the most energetic TUMS, namely hot flow anomalies, foreshock bubbles, travelling foreshocks and foreshock compressional boundaries. The space weather phenomena associated with TUMS tend to be more localized and less intense compared to geomagnetic storms. However, the quiet time space weather may occur more often since, especially during solar minima, quiet SW periods prevail over the perturbed times.

1 figure, 1 table

References in corpus (7)

• Global impacts of a Foreshock Bubble: Magnetosheath, magnetopause and ground-based observations
• The role of pressure gradients in driving sunward magnetosheath flows and magnetopause motion
• Large-scale jets in the magnetosheath and plasma penetration across the magnetopause: THEMIS observations
• Traveling foreshocks and transient foreshock phenomena
• Causes of jets in the quasi-perpendicular magnetosheath
• Transient Foreshock Structures Upstream of Mars: Implications of the Small Martian Bow Shock
• Hot flow anomaly remnant in the far geotail?

Cited by in corpus (4)

• Radial Diffusion Driven by Spatially Localized ULF Waves in the Earth's Magnetosphere
• Multi-Mission Observations of Relativistic Electrons and High-Speed Jets Linked to Shock Generated Transients
• Different Transient Phenomena at the Edges of Traveling Foreshocks
• Compressive Structures in the Foreshock of Collisionless Shocks